Sleep,excercise and human growth hormoneCreated by:
Does sleep make it easier to exercise or does exercise make it easier to sleep. Both. And human growth hormone is tied up in both.
Human growth hormone (often abbreviated HGH, or GH for growth hormone, or hGH) is an important part of the body’s endocrine system and is especially active in the growing child’s maturation. (It is not the only physiological factor that makes kids get taller.) HGH is released by the brain into the bloodstream during sleep, and its release is part of the repair and restoration function of sleep.
The hormone is a complex protein produced by the pituitary gland in the brain, and in addition to promoting growth in childhood, it helps maintain healthy bodily tissue even during adulthood. The pituitary gland releases growth hormone non-continuously – the release looks like a pulse. Sleep and exercise induce the release of the hormone.
In normal healthy people, the major period of HGH release is in the first period of Stage 3 sleep during the night.
If a person stays up all night when he or she normally sleeps, there is no surge in growth hormone release. After a period of sleep deprivation, there is extra hormone released when sleep is resumed, and the pattern departs from the normal pulse during slow-wave sleep.
Scientists did an experiment where they hid people away from daylight and other environmental cues that act as circadian hooks. The subjects were allowed to set their own sleep schedule which became disentrained from the 24-hr cycle. This experiment has been done many times, but in this case the scientists measured the blood levels of growth hormone and followed when the pituitary gland released the hormone. They found the peak levels of hormone released during sleep decreased significantly. The first slow wave sleep (SWS) period of the night was shorter and the first REM period happened sooner.
The researchers concluded that the timing of sleep stages can change the amount of hormone released during sleep.
In middle age, the brain starts producing lower quantities of growth hormone. This has spurred interest in use of supplemental hormones to keep the body young. The effectiveness of this is not widely accepted by credible medical authorities, and is not approved by the FDA. (Supplemental HGH is approved for some pathologies, but not for general aging.)